centre of this basin is a round hole, about ten feet in diameter,
out of which the water springs. This hole is the mouth of a
circular well, between seventy and eighty feet in depth. It is down
this well that the jet retires on its disappearance; and it drags
along with it all the water out of the basin, leaving both basin
and well quite empty, without even a puff of steam coming out of
the hole. In this state of emptiness the basin and well remain for
several hours. Suddenly the water begins to rise in the well,
overflowing till it fills the basin. Loud explosions are heard from
below, and the ground trembles. Then, with amazing violence, up
springs a vast column of boiling water, surmounted by clouds of
steam, which obscure the air. This first jet is followed by several
others in rapid succession, to the number of sixteen or eighteen;
the last jet being usually the greatest of all, and attaining a
height of nearly a hundred feet. In some instances it has risen to
a height of a hundred and fifty feet; and one particular jet was
measured which rose to the amazing height of two hundred and twelve
feet.

The action of the fountain seldom continues more than about five
minutes at a time, and then a repose of several hours ensues. If
left to itself, the periods of the fountain's activity, though not
quite regular, generally recur at intervals of six or seven hours.
But they may be hastened by throwing big stones down the well. This
not only hurries the eruption of the jet, but increases its energy,
and the stones are thrown out with great force by the column of
boiling water; the loudness of the explosions being also
considerably augmented.

There are several other geysers in the island besides this big one.